Cleaning pots and connections is usually a temporary fix... Since the parts are under current usually the ionization and oxidation processes are accelerated... and it acts on the pots from inside the out... The grease or cleaner sits on the surface and eventually is cleared away by the oxidation from within... Making the sound come back. To completely fix the problem pick up a new pot at stew-mac.com Try to look for a sealed pot for the best performance and longest life. If the sound is coming from the gear... it wouldn't sound through the amp... but since you say it is coming through even over heavy distortion... that leads me to believe it's the pot itself... Pots range from 5-20 dollars.